The present invention relates to threat detection systems and, in particular, it concerns a detection system for detecting rockets or missiles launched from short range towards a platform.
In the continuing conflict in Iraq, shoulder fired rocket propelled grenades (RPGs) were once again proven a potent weapon. RPGs have performed impressively in all post WWII conflicts, especially in Vietnam, Afghanistan and Chechnya. Designed specifically for close combat operations, this reliable, simple and affordable weapon poses a serious threat to even the heaviest tanks when used by determined fighters, in both urban and guerrilla warfare. Inexperienced RPG operators can engage a stationary target effectively from 150-300 meters, while experienced users could kill a target at up to 500 meters, and moving targets at 300 meters. In post war Iraq, RPGs have caused the death of over fifty percent of U.S. soldiers killed in action.
One approach for protecting tanks, armored vehicles, light vehicles and stationary platforms from incoming rocket propelled grenades (“RPG”s) or anti-tank missiles is the use of an active protection system. Active protection systems are composed of two subsystems: a detection system for detecting the incoming threat; and a countermeasure system for engaging the threat so as to neutralize the threat or at least reduce its efficacy. A range of countermeasure technologies have been used for active protection systems against RPGs and anti-tank missiles. Examples include: “soft-kill” technology such as direct infrared countermeasures (DIRCM); “hard-kill” technology such as the fragment ejection system of the Arena-E system (KBM, Russia); and airbag deflection systems.
The predominant choice for the detection technology of an active protection system is a panoramic radar system. It has been found, however, that for short range applications of less than 100 meters, panoramic radar becomes unreliable, failing to provide sufficient precision or warning time for reliably operating countermeasures. As an alternative, systems have been proposed employing bolometric imaging sensors sensitive in the 8-13 micron wavelength range to detect the launch flash of a threat. Bolometric imaging sensors, however, provide relatively low sensor resolution, requiring multiple sensors to cover a panoramic field of view. This fact, combined with the high unit cost of such sensors, renders such detection systems economically unviable for large scale installation on a wide range of platforms.
There is therefore a need for an optical threat detection system which would use readily available low-cost components to provide effective threat detection at ranges not reliably covered by radar-based detection systems. It would also be advantageous to combine such an optical system with a radar-based detection system to provide effective short and long range detection of offensive projectiles, and for actuating a countermeasure system.